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  • Placing & deleting element(s) from a object (stack)

    - by Chris
    Hello, Initialising 2 stack objects: Stack s1 = new Stack(), s2 = new Stack(); s1 = 0 0 0 0 0 0 0 0 0 0 (array of 10 elements wich is empty to start with) top:0 const int Rows = 10; int[] Table = new int[Rows]; public void TableStack(int[] Table) { for (int i=0; i < Table.Length; i++) { } } My question is how exactly do i place a element on a stack (push) or take a element from the stack (pop) as the following: Push: s1.Push(5); // s1 = 5 0 0 0 0 0 0 0 0 0 (top:1) s1.Push(9); // s1 = 5 9 0 0 0 0 0 0 0 0 (top:2) Pop: int number = s1.Pop(); // s1 = 5 0 0 0 0 0 0 0 0 0 0 (top:1) 9 got removed Do i have to use get & set, and if so how exactly do i implent this with a array? Not really sure what to exactly use for this. Any hints highly appreciated. The program uses the following driver to test the Stack class (wich cannot be changed or modified): public void ExecuteProgram() { Console.Title = "StackDemo"; Stack s1 = new Stack(), s2 = new Stack(); ShowStack(s1, "s1"); ShowStack(s2, "s2"); Console.WriteLine(); int getal = TryPop(s1); ShowStack(s1, "s1"); TryPush(s2, 17); ShowStack(s2, "s2"); TryPush(s2, -8); ShowStack(s2, "s2"); TryPush(s2, 59); ShowStack(s2, "s2"); Console.WriteLine(); for (int i = 1; i <= 3; i++) { TryPush(s1, 2 * i); ShowStack(s1, "s1"); } Console.WriteLine(); for (int i = 1; i <= 3; i++) { TryPush(s2, i * i); ShowStack(s2, "s2"); } Console.WriteLine(); for (int i = 1; i <= 6; i++) { getal = TryPop(s2); //use number ShowStack(s2, "s2"); } }/*ExecuteProgram*/ Regards.

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  • Silverlight with MVVM Inheritance: ModelView and View matching the Model

    - by moonground.de
    Hello Stackoverflowers! :) Today I have a special question on Silverlight (4 RC) MVVM and inheritance concepts and looking for a best practice solution... I think that i understand the basic idea and concepts behind MVVM. My Model doesn't know anything about the ViewModel as the ViewModel itself doesn't know about the View. The ViewModel knows the Model and the Views know the ViewModels. Imagine the following basic (example) scenario (I'm trying to keep anything short and simple): My Model contains a ProductBase class with a few basic properties, a SimpleProduct : ProductBase adding a few more Properties and ExtendedProduct : ProductBase adding another properties. According to this Model I have several ViewModels, most essential SimpleProductViewModel : ViewModelBase and ExtendedProductViewModel : ViewModelBase. Last but not least, according Views SimpleProductView and ExtendedProductView. In future, I might add many product types (and matching Views + VMs). 1. How do i know which ViewModel to create when receiving a Model collection? After calling my data provider method, it will finally end up having a List<ProductBase>. It containts, for example, one SimpleProduct and two ExtendedProducts. How can I transform the results to an ObservableCollection<ViewModelBase> having the proper ViewModel types (one SimpleProductViewModel and two ExtendedProductViewModels) in it? I might check for Model type and construct the ViewModel accordingly, i.e. foreach(ProductBase currentProductBase in resultList) if (currentProductBase is SimpleProduct) viewModels.Add( new SimpleProductViewModel((SimpleProduct)currentProductBase)); else if (currentProductBase is ExtendedProduct) viewModels.Add( new ExtendedProductViewModels((ExtendedProduct)currentProductBase)); ... } ...but I consider this very bad practice as this code doesn't follow the object oriented design. The other way round, providing abstract Factory methods would reduce the code to: foreach(ProductBase currentProductBase in resultList) viewModels.Add(currentProductBase.CreateViewModel()) and would be perfectly extensible but since the Model doesn't know the ViewModels, that's not possible. I might bring interfaces into game here, but I haven't seen such approach proven yet. 2. How do i know which View to display when selecting a ViewModel? This is pretty the same problem, but on a higher level. Ended up finally having the desired ObservableCollection<ViewModelBase> collection would require the main view to choose a matching View for the ViewModel. In WPF, there is a DataTemplate concept which can supply a View upon a defined DataType. Unfortunately, this doesn't work in Silverlight and the only replacement I've found was the ResourceSelector of the SLExtensions toolkit which is buggy and not satisfying. Beside that, all problems from Question 1 apply as well. Do you have some hints or even a solution for the problems I describe, which you hopefully can understand from my explanation? Thank you in advance! Thomas

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  • Annoying Captcha >> How to programm a form that can SMELL difference between human and robot?

    - by Sam
    Hi folks. On the comment of my old form needing a CAPTHA, I felt I share my problem, perhaps you recognize it and find its time we had better solutions: FACTUAL PROBLEM I know most of my clients (typical age= 40~60) hate CAPTCHA things. Now, I myself always feel like a robot, when I have to sueeze my eyes and fill in the strange letters from the Capcha... Sometimes I fail! Go back etc. Turnoff. I mean comon its 2011, shouldnt the forms have better A.I. by now? MY NEW IDEA (please dont laugh) Ive thought about it and this is my idea's to tell difference between human and robot: My idea is to give credibility points. 100 points = human 0% = robot. require real human mouse movements require mousemovements that dont follow any mathematical pattern require non-instantaneous reading delays, between load and first input in form when typing in form, delays are measured between letters and words approve as human when typical human behaviour measured (deleting, rephrasing etc) dont allow instant pasting or all fields give points for real keyboard pressures retract points for credibility when hyperlinks in form Test wether fake email field (invisible by human) is populated (suggested by Tomalak) when more than 75% human cretibility, allow to be sent without captcha when less than 25% human crecibility, force captcha puzzle to be sure Could we write a A.I. PHP that replaces the human-annoying capthas, meanwhile stopping most spamservers filing in the data? Not only for the fun of it, but also actually to provide a 99% better alternative than CAPTHCA's. Imagine the userfriendlyness of your forms! Your site distinguishing itself from others, showing your audience your sites KNOWS the difference between a robot and a human. Imagine the advangage. I am trying to capture the essense of that distinguishing edge. PROGRAMMING QUESTION: 1) Are such things possible to programm? 2) If so how would you start such programm? 3) Are there already very good working solutions available elsewhere? 4) If it isn't so hard, your are welcome to share your answer/solutions below. 5) upon completion of hints and new ideas, could this page be the start of a new AI captcha, OR should I forget about it and just go with the flow, forget about the whole AI dream, and use captcha like everyone else.

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  • Stuck with Regular Expression code to apply HTML tag to text but exclude if inside <?> tag

    - by James Buckingham
    Hi there. I'm trying to write a bit of regex which would go through some text, written by our Editors, and apply an <acronym> tag to the first instance it finds of an abbreviation set we hold in our "Glossary of Terms". So for this example I've used the abbreviation ITS. 1st thing I thought I'd do is setup an example with a mix of scenerios I could test against, i.e. ITS sitting with punctuation, in HTML tags & ones that we've applied this to already (in other words the script has run through this before, so no need to do again). I'm almost there but just got stuck at the last point :-(. Here's the regex I've got so far - <[^<|]+?>?>ITS<[^<]+?>|ITS The Example - FROM ( EVERY ITS IN BOLD TO BE WRAPPED WITH ACRONYM ): I want you to tag thisITS, but not this wrapped one - <acronym title="ITS" id="thisIsATest">ITS</acronym> This is another test as I still want to update <p>ITS</p> that have other HTML tags wrapped around them.` ITS want ones that start sentences and ones that finish ITS. ITS, and ones which are wrapped in punctuation.` Test link: <a href="index.cfm>ITS</a> AND I WANT THIS CHANGE TO : I want you to tag this <acronym title="ITS">ITS</acronym>, but not this wrapped one - <acronym title="ITS">ITS</acronym> This is another test as I still want to update <acronym title="ITS">ITS</acronym> that have other HTML tags wrapped around them.` <acronym title="ITS">ITS</acronym> want ones that start sentences and ones that finish <acronym title="ITS">ITS</acronym>. <acronym title="ITS">ITS</acronym>, and ones which are wrapped in punctuation. Test link: <acronym title="ITS"><a href="index.cfm>ITS</a></acronym> Are there any Reg Ex experts out there that could help me finish this off? Any other hints tips would also be appreciated. Thanks a lot, James P.S. This is going to be placed in a ColdFusion application if that helps anyone in specific syntax.

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  • AccessControlException: access denied - caller function failed to load properties file

    - by Michael Mao
    Hi all: I am having a jar archive environment which is gonna call my class in a folder like this: java -jar "emarket.jar" ../tournament 100 My compiled class is deployed into the ../tournament folder, this command runs well. After I changed my code to load a properties file, it gets the following exception message: Exception in thread "main" java.security.AccessControlException: access denied (java.io.FilePermission agent.properties read) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkRead(Unknown Source) at java.io.FileInputStream.<init>(Unknown Source) at java.io.FileInputStream.<init>(Unknown Source) at Agent10479475.getPropertiesFromConfigFile(Agent10479475.java:110) at Agent10479475.<init>(Agent10479475.java:100) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at java.lang.Class.newInstance0(Unknown Source) at java.lang.Class.newInstance(Unknown Source) at emarket.client.EmarketSandbox.instantiateClientObjects(EmarketSandbox.java:92) at emarket.client.EmarketSandbox.<init>(EmarketSandbox.java:27) at emarket.client.EmarketSandbox.main(EmarketSandbox.java:166) I am wondering why this security checking will fail. I issue the getPropertitiesFromConfigFile() function inside my class's default constructor, like this: public class Agent10479475 extends AbstractClientAgent { //default constructor public Agent10479475() { //set all properties to their default values in constructor FT_THRESHOLD = 400; FT_THRESHOLD_MARGIN = 50; printOut("Now loading properties from a config file...", ""); getPropertiesFromConfigFile(); printOut("Finished loading",""); } private void getPropertiesFromConfigFile() { Properties props = new Properties(); try { props.load(new FileInputStream("agent.properties")); FT_THRESHOLD = Long.parseLong(props.getProperty("FT_THRESHOLD")); FT_THRESHOLD_MARGIN = Long.parseLong(props.getProperty("FT_THRESHOLD_MARGIN ")); } catch(java.io.FileNotFoundException fnfex) { printOut("CANNOT FIND PROPERTIES FILE :", fnfex); } catch(java.io.IOException ioex) { printOut("IOEXCEPTION OCCURED :", ioex); } } } My class is loading its own .properties file under the same folder. why would the Java environment complains about such a denial of access? Must I config the emarket.client.EmarketSandbox class, which is not written by me and stored inside the emarket.jar, to access my agent.properties file? Any hints or suggestions is much appreciated. Many thanks in advance.

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  • What are the types and inner workings of a query optimizer?

    - by Frank Developer
    As I understand it, most query optimizers are cost-based. Some can be influenced by hints like FIRST_ROWS(). Others are tailored for OLAP. Is it possible to know more detailed logic about how Informix IDS and SE's optimizers decide what's the best route for processing a query, other than SET EXPLAIN? Is there any documentation which illustrates the ranking of SELECT statements? I would imagine that "SELECT col FROM table WHERE ROWID = n" ranks 1st. What are the rest of them?.. If I'm not mistaking, Informix's ROWID is a SERIAL(INT) which allows for a max. of 2GB nrows, or maybe it uses INT9 for TB's nrows?.. However, I think Oracle uses HEX values for ROWID. Too bad ROWID can't be oftenly used, since a rows ROWID can change. So maybe ROWID is used by the optimizer as a counter? Perhaps, it could be used for implementing the query progress idea I mentioned in my "Begin viewing query results before query completes" question? For some reason, I feel it wouldn't be that difficult to report a query's progress while being processed, perhaps at the expense of some slight overhead, but it would be nice to know ahead of time: A "Google-like" estimate of how many rows meet a query's criteria, display it's progress every 100, 200, 500 or 1,000 rows, give users the ability to cancel it at anytime and start displaying the qualifying rows as they are being put into the current list, while it continues searching?.. This is just one example, perhaps we could think other neat/useful features, the ingridients are more or less there. Perhaps we could fine-tune each query with more granularity than currently available? OLTP queries tend to be mostly static and pre-defined. The "what-if's" are more OLAP, so let's try to add more control and intelligence to it? So, therefore, being able to more precisely control, not "hint-influence" a query is what's needed and therefore it would be necessary to know how the optimizers logic is programmed. We can then have Dynamic SELECT and other statements for specific situations! Maybe even tell IDS to read blocks of indexes nodes at-a-time instead of one-by-one, etc. etc.

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  • SurfaceView for Camera Preview won't get destroyed when pressing Power-Botton

    - by for3st
    I want to implement a camera preview. For that I have a custom View CameraView extends ViewGroup that in the constructor programatically creates an surfaceView. I have the following components (higly simplified for beverity): ScannerFragment.java public View onCreateView(..) { //inflate view and get cameraView } public void onResume() { //open camera -> set rotation -> startPreview (in a thread) -> //set preview callback -> start decoding worker } public void onPause() { // stop decoding worker -> stop Preview -> release camera } CameraView.java extends ViewGroup public void setUpCalledInConstructor(Context context) { //create a surfaceview and add it to this viewgroup -> //get SurfaceHolder and set callback } /* SurfaceHolder.Callback */ public void surfaceCreated(SurfaceHolder holder) { camera.setPreviewDisplay(holder); } public void surfaceDestroyed(SurfaceHolder holder) { //NOTHING is done here } public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { camera.getParameters().setPreviewSize(previewSize.width, previewSize.height); } fragment_scanner.xml <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent"> <com.myapp.camera.CameraView android:id="@+id/cameraPreview" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout> I think I have set the lifecycle correct (getting resources onResume(), releasing it onPause() roughly said) and the following works just fine: pressing home and returning pressing Taskswitcher and returning rotation But one thing doesn't work and that is when I press the power-button on the device and then return to the camera-preview. The result is: the preview is stuck with the image that was last captured before button was pressed. If I rotate it works fine again, since it will get through the lifecycle. After some research I found out that this is probably due to the fact that surfaceView won't get destroyed when the power-button is pressed, i.e. SurfaceHolder.Callback.surfaceDestroyed(SurfaceHolder holder) won't be called. And in fact when I compare the (very verbose) log output of the home-button-case and the power-button-case it's the same except that 'surfaceDestroyed' won't get called. So far I found no solution whatsoever to work around it. I purposely avoid any resource cleaning code in my surfaceDestroyed(), but this does not help. My idea was to manually destroy the surfaceView like asked in this question but this seems not possible. I also tested other applications with surfaceViews/cameras and they don't seem to have this issue. So I would appreciate any hints or tips on that.

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  • Available Coroutine Libraries in Java

    - by JUST MY correct OPINION
    I would like to do some stuff in Java that would be clearer if written using concurrent routines, but for which full-on threads are serious overkill. The answer, of course, is the use of coroutines, but there doesn't appear to be any coroutine support in the standard Java libraries and a quick Google on it brings up tantalising hints here or there, but nothing substantial. Here's what I've found so far: JSIM has a coroutine class, but it looks pretty heavyweight and conflates, seemingly, with threads at points. The point of this is to reduce the complexity of full-on threading, not to add to it. Further I'm not sure that the class can be extracted from the library and used independently. Xalan has a coroutine set class that does coroutine-like stuff, but again it's dubious if this can be meaningfully extracted from the overall library. It also looks like it's implemented as a tightly-controlled form of thread pool, not as actual coroutines. There's a Google Code project which looks like what I'm after, but if anything it looks more heavyweight than using threads would be. I'm basically nervous of something that requires software to dynamically change the JVM bytecode at runtime to do its work. This looks like overkill and like something that will cause more problems than coroutines would solve. Further it looks like it doesn't implement the whole coroutine concept. By my glance-over it gives a yield feature that just returns to the invoker. Proper coroutines allow yields to transfer control to any known coroutine directly. Basically this library, heavyweight and scary as it is, only gives you support for iterators, not fully-general coroutines. The promisingly-named Coroutine for Java fails because it's a platform-specific (obviously using JNI) solution. And that's about all I've found. I know about the native JVM support for coroutines in the Da Vinci Machine and I also know about the JNI continuations trick for doing this. These are not really good solutions for me, however, as I would not necessarily have control over which VM or platform my code would run on. (Indeed any bytecode manipulation system would suffer similar problems -- it would be best were this pure Java if possible. Runtime bytecode manipulation would restrict me from using this on Android, for example.) So does anybody have any pointers? Is this even possible? If not, will it be possible in Java 7? Edited to add: Just to ensure that confusion is contained, this is a related question to my other one, but not the same. This one is looking for an existing implementation in a bid to avoid reinventing the wheel unnecessarily. The other one is a question relating to how one would go about implementing coroutines in Java should this question prove unanswerable. The intent is to keep different questions on different threads.

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  • Seeking STL-aware c++filt

    - by Don Wakefield
    In my development environment, I'm compiling a code base using GNU C++ 3.4.6. Code is under development, and unfortunately crashes now and then. It's nice to be able to run the traceback through a demangler, and I use c++filt 3.4. The problem comes when functions have a number of STL parameters. Consider My_callback::operator()( Status&, std::set<std::string> const&, std::vector<My_parameter*> const&, My_attribute_set const&, std::vector<My_parameter_base*> const&, std::vector<My_parameter> const&, std::set<std::string> const& ) { // ... } When this function is in the traceback, the mangled output on my platform is: (_ZN30My_callbackclER11StatusRKSt3setISsSt4lessISsESaISsEERKSt6vectorIP13My_parameterSaISB_EERK17My_attribute_setRKS9_IP18My_parameter_baseSaISK_EERKS9_ISA_SaISA_EES8_+0x76a) [0x13ffdaa] c++filt kindly demangles it to (My_callback::operator()(Status&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&, std::vector<My_parameter*, std::allocator<My_parameter*> > const&, My_attribute_set const&, std::vector<My_parameter_base*, std::allocator<My_parameter_base*> > const&, std::vector<My_parameter, std::allocator<My_parameter> > const&, std::set<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > const&)+0x76a) [0x13ffdaa] This is the same problem as compiler errors encountered when using templates. However, the STL is a fairly regular and recognizable package of templates. So what I'm hoping is that someone out there has created an enhanced version of c++filt which would dump something closer to the original function signature. Any hints?

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  • How to embed html table into the body of email

    - by Michael Mao
    Hi all: I am sending info to target email via PHP native mail() method right now. Everything else works fine but the table part troubles me the most. See sample output : Dear Michael Mao : Thank you for purchasing flight tickets with us, here is your receipt : Your tickets will be delivered by mail to the following address : Street Address 1 : sdfsdafsadf sdf Street Address 2 : N/A City : Sydney State : nsw Postcode : 2 Country : Australia Credit Card Number : *************1234 Your purchase details are recorded as : <table><tr><th class="delete">del?</th><th class="from_city">from</th><th class="to_city">to</th><th class="quantity">qty</th><th class="price">unit price</th><th class="price">total price</th></tr><tr class="evenrow" id="Sydney-Lima"><td><input name="isDeleting" type="checkbox"></td><td>Sydney</td><td>Lima</td><td>1</td><td>1030.00</td><td>1030</td></tr><tr class="oddrow" id="Sydney-Perth"><td><input name="isDeleting" type="checkbox"></td><td>Sydney</td><td>Perth</td><td>3</td><td>340.00</td><td>1020</td></tr><tr class="totalprice"><td colspan="5">Grand Total Price</td><td id="grandtotal">2050</td></tr></table> The source of table is directly taken from a webpage, exactly as the same. However, Gmail, Hotmail and most of other emails will ignore to render this as a table. So I am wondering, without using Outlook or other email sending agent software, how could I craft a embedded table for the PHP mail() method to send? Current code snippet corresponds to table generation : $purchaseinfo = $_POST["purchaseinfo"]; //if html tags are not to be filtered in the body of email $stringBuilder .= "<table>" .stripslashes($purchaseinfo) ."</table>"; //must send json response back to caller ajax request if(mail($email, 'Your purchase information on www.hardlyworldtravel.com', $emailbody, $headers)) echo json_encode(array("feedback"=>"successful")); else echo json_encode(array("feedback"=>"error")); Any hints and suggestions are welcomed, thanks a lot in advance.

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  • Event sourcing: Write event before or after updating the model

    - by Magnus
    I'm reasoning about event sourcing and often I arrive at a chicken and egg problem. Would be grateful for some hints on how to reason around this. If I execute all I/O-bound processing async (ie writing to the event log) then how do I handle, or sometimes even detect, failures? I'm using Akka Actors so processing is sequential for each event/message. I do not have any database at this time, instead I would persist all the events in an event log and then keep an aggregated state of all the events in a model stored in memory. Queries are all against this model, you can consider it to be a cache. Example Creating a new user: Validate that the user does not exist in model Persist event to journal Update model (in memory) If step 3 breaks I still have persisted my event so I can replay it at a later date. If step 2 breaks I can handle that as well gracefully. This is fine, but since step 2 is I/O-bound I figured that I should do I/O in a separate actor to free up the first actor for queries: Updating a user while allowing queries (A0 = Front end/GUI actor, A1 = Processor Actor, A2 = IO-actor, E = event bus). (A0-E-A1) Event is published to update user 'U1'. Validate that the user 'U1' exists in model (A1-A2) Persist event to journal (separate actor) (A0-E-A1-A0) Query for user 'U1' profile (A2-A1) Event is now persisted continue to update model (A0-E-A1-A0) Query for user 'U1' profile (now returns fresh data) This is appealing since queries can be processed while I/O-is churning along at it's own pace. But now I can cause myself all kinds of problems where I could have two incompatible commands (delete and then update) be persisted to the event log and crash on me when replayed up at a later date, since I do the validation before persisting the event and then update the model. My aim is to have a simple reasoning around my model (since Actor processes messages sequentially single threaded) but not be waiting for I/O-bound updates when Querying. I get the feeling I'm modeling a database which in itself is might be a problem. If things are unclear please write a comment.

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  • Need Help with Consolidating RoR Google Map Results

    - by Kevin
    I have a project that returns geocoded results within 20 miles of the user. I want these results grouped on the map by zip code, then within the info window show the individual results. The code posted below works, but for some reason it only displays the 1.png rather than looking at the results and using the correct .png icon associated with the number. When I look at the infowindows, it displays the correct png like "/images/2.png" or "/images/5.png" but the actual image is always 1. @ziptickets = Ticket.find(:all, :origin => coords, :select => 'DISTINCT zip, lat, lng', :within => @user.distance_to_travel, :conditions => "status_id = 1") for t in @ziptickets zips = Ticket.find(:all, :conditions => ["zip = ?", t.zip]) currentzip = t.zip.to_s tixinzip = zips.size.to_s imagelocation = "/images/" + tixinzip + ".png" shadowlocation = "/images/" + tixinzip + "s.png" @map.icon_global_init(GIcon.new(:image => imagelocation, :shadow => shadowlocation, :shadow_size => GSize.new(60,40), :icon_anchor => GPoint.new(20,20), :info_window_anchor => GPoint.new(9,2)), "test") newicon = Variable.new("test") new_marker = GMarker.new([t.lat, t.lng], :icon => newicon, :title => imagelocation, :info_window => currentzip) @map.overlay_init(new_marker) end I tried changing the last part of the mapicon from: :info_window_anchor => GPoint.new(9,2)), "test") newicon = Variable.new("test") to: :info_window_anchor => GPoint.new(9,2)), currentzip) newicon = Variable.new(currentzip) but the strangest thing is that any string that has numbers in it causes the map to fail to render in the view and just show a blank screen... same if I replace it with :info_window_anchor => GPoint.new(9,2)), "123") newicon = Variable.new("123") Any advice would be helpful... also it runs a bit slower than my previous code which just set up 4 standard icons and used them outside of the loop so any hints as to speed up execution would be appreciated greatly. Thanks!

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  • How to Sync CI (Hudson) Activity into an existing automated Build Process (phing, svn)?

    - by maraspin
    OUR CURRENT BUILD PROCESS We're a small team of developers (2 to 4 people depending on project) who currently use Phing to deploy code to a staging environment, before going live. We keep our code in a SVN repo, where the trunk holds current active development and, at certain times, we do make branches that we test and then (if successful), tag and export to the staging env. If everything goes well there too, we finally deploy'em in production servers. Actions are highly automated, but always triggered by human intervention. THE DOUBT We'd now like to introduce Continuous Integration (with Hudson) in the process; unfortunately we have a few doubts about activity syncing, since we're afraid that CI could somewhat interfere with our build process and cause certain problems. Considering that an automated CI cycle has a certain frequency of automatically executed actions, we see 2 possible cases for "integration", each with its own problems: Case A: each CI cycle produces a new branch with its own name; we do use such a name to manually (through phing as it happens now) export the code from the SVN to the staging env. The problem I see here is that (unless specific countermeasures are taken - IE deletion) the number of branches we have can easily grow out of control (let's suppose we commit often, so that we have a fresh new build/branch every N minutes). Case B: each CI cycle creates a new branch named 'current', which is then tagged with a unique name only when we manually decide to export it to staging; the current branch, at any case is then deleted, as soon as the next CI cycle starts up. The problem we see here is that a new cycle could kick in while someone is tagging/exporting the 'current' branch to staging thus creating an inconsistent build (but maybe here I'm just too pessimist, since I confess I don't know whether SVN offers some built-in protection against this). With all this being said, I was wondering if anyone with similar experiences could be so kind to give us some hints on the subject, since none of the approaches depicted above looks completely satisfing to us. Is there something important we just completely left off in the overall picture? Thanks for your attention & (in advance) for your help!

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  • Coroutines in Java

    - by JUST MY correct OPINION
    I would like to do some stuff in Java that would be clearer if written using concurrent routines, but for which full-on threads are serious overkill. The answer, of course, is the use of coroutines, but there doesn't appear to be any coroutine support in the standard Java libraries and a quick Google on it brings up tantalising hints here or there, but nothing substantial. Here's what I've found so far: JSIM has a coroutine class, but it looks pretty heavyweight and conflates, seemingly, with threads at points. The point of this is to reduce the complexity of full-on threading, not to add to it. Further I'm not sure that the class can be extracted from the library and used independently. Xalan has a coroutine set class that does coroutine-like stuff, but again it's dubious if this can be meaningfully extracted from the overall library. It also looks like it's implemented as a tightly-controlled form of thread pool, not as actual coroutines. There's a Google Code project which looks like what I'm after, but if anything it looks more heavyweight than using threads would be. I'm basically nervous of something that requires software to dynamically change the JVM bytecode at runtime to do its work. This looks like overkill and like something that will cause more problems than coroutines would solve. Further it looks like it doesn't implement the whole coroutine concept. By my glance-over it gives a yield feature that just returns to the invoker. Proper coroutines allow yields to transfer control to any known coroutine directly. Basically this library, heavyweight and scary as it is, only gives you support for iterators, not fully-general coroutines. The promisingly-named Coroutine for Java fails because it's a platform-specific (obviously using JNI) solution. And that's about all I've found. I know about the native JVM support for coroutines in the Da Vinci Machine and I also know about the JNI continuations trick for doing this. These are not really good solutions for me, however, as I would not necessarily have control over which VM or platform my code would run on. (Indeed any bytecode manipulation system would suffer similar problems -- it would be best were this pure Java if possible. Runtime bytecode manipulation would restrict me from using this on Android, for example.) So does anybody have any pointers? Is this even possible? If not, will it be possible in Java 7?

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  • Recursion problem; completely lost

    - by timeNomad
    So I've been trying to solve this assignment whole day, just can't get it. The following function accepts 2 strings, the 2nd (not 1st) possibly containing *'s (asterisks). An * is a replacement for a string (empty, 1 char or more), it can appear appear (only in s2) once, twice, more or not at all, it cannot be adjacent to another * (ab**c), no need to check that. public static boolean samePattern(String s1, String s2) It returns true if strings are of the same pattern. It must be recursive, not use any loops, static & global variables. Can use local variables & method overloading. Can use only these methods: charAt(i), substring(i), substring(i, j), length(). Examples: 1: TheExamIsEasy; 2: "The*xamIs*y" --- true 1: TheExamIsEasy; 2: "Th*mIsEasy*" --- true 1: TheExamIsEasy; 2: "*" --- true 1: TheExamIsEasy; 2: "TheExamIsEasy" --- true 1: TheExamIsEasy; 2: "The*IsHard" --- FALSE I tried comparing the the chars one by one using charAt until an asterisk is encountered, then check if the asterisk is an empty one by comparing is successive char (i+1) with the char of s1 at position i, if true -- continue recursion with i+1 as counter for s2 & i as counter for s1; if false -- continue recursion with i+1 as counters for both. Continue this until another asterisk is found or end of string. I dunno, my brain loses track of things, can't concentrate, any pointers / hints? Am I in the right direction? Also, it's been told that a backtracking technique is to be used to solve this. My code so far (doesn't do the job, even theoretically): public static boolean samePattern(String s1, String s2) { if (s1.equals(s2) || s2 == "*") { return true; } return samePattern(s1, s2, 1); } public static boolean samePattern(String s1, String s2, int i) { if (s1.equals(s2)) return true; if (i == s2.length() - 1) // No *'s found -- not same pattern. return false; if (s1.substring(0, i).equals(s2.substring(0, i))) samePattern(s1, s2, i+1); else if (s2.charAt(i-1) == '*') samePattern(s1.substring(0, i-1), s2.substring(0, i), 1); // new smaller strings. else samePattern(s1.substring(1), s2, i); }

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  • Generic linked list in c++

    - by itsaboy
    I have been struggling for too long a time now with a rather simple question about how to create a generic linked list in c++. The list should be able contain several types of structs, but each list will only contain one type of struct. The problem arises when I want to implement the getNode() function [see below], because then I have to specify which of the structs it should return. I have tried to substitute the structs with classes, where the getNode function returns a base class that is inherited by all the other classes, but it still does not do the trick, since the compiler does not allow the getNode function to return anything but the base class then. So here is some code snippet: typedef struct struct1 { int param1; (...) } struct1; typedef struct struct2 { double param1; (...) } struct2; typedef struct node { struct1 data; node* link; } node; class LinkedList { public: node *first; int nbrOfNodes; LinkedList(); void addNode(struct1); struct1 getNode(); bool isEmpty(); }; LinkedList::LinkedList() { first = NULL; nbrOfNodes = 0; } void LinkedList::addNode(struct1 newData) { if (nbrOfNodes == 0) { first = new node; first->data = newData; } else { node *it = first; for (int i = 0; i < nbrOfNodes; i++) { it = it->link; } node *newNode = new node; newNode->data = newData; it->link = newNode; } nbrOfNodes++; } bool LinkedList::isEmpty() { return !nbrOfNodes; } struct1 LinkedList::getNode() { param1 returnData = first->data; node* deleteNode = first; nbrOfNodes--; if (nbrOfNodes) first = deleteNode->link; delete deleteNode; return returnData; } So the question, put in one sentence, is as follows: How do I adjust the above linked list class so that it can also be used for struct2, without having to create a new almost identical list class for struct2 objects? As I said above, each instance of LinkedList will only deal with either struct1 or struct2. Grateful for hints or help

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  • Any socket programmers out there? How can I obtain the IPv4 address of the client?

    - by Dr Dork
    Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code setup to listen for incoming TCP connection requests from clients after the parent socket has been created and is set to listen... int sockfd, newfd; unsigned int len; socklen_t sin_size; char msg[]="Test message sent"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char ip[INET6_ADDRSTRLEN]; . . //parent socket creation and listen code omitted for simplicity . //wait for connection requests from clients while(1) { //Returns the socketID and address of client connecting to socket if( ( newfd = accept(sockfd, (struct sockaddr *)&client, &len) ) == -1 ){ perror("Accept"); exit(-1); } if( (rv = recv(newfd, buf, MAXLEN-1, 0 )) == -1) { perror("Recv"); exit(-1); } struct sockaddr_in *clientAddr = ( struct sockaddr_in *) get_in_addr((struct sockaddr *)&client); inet_ntop(client.ss_family, clientAddr, ip, sizeof ip); printf("Receive from %s: query type is %s\n", ip, buf); if( ( st = send(newfd, msg, strlen(msg), 0)) == -1 ) { perror("Send"); exit(-1); } //ntohs is used to avoid big-endian and little endian compatibility issues printf("Send %d byte to port %d\n", ntohs(clientAddr->sin_port) ); close(newfd); } } I found the get_in_addr function online and placed it at the top of my code and use it to obtain the IP address of the client connecting... // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); } return &(((struct sockaddr_in6*)sa)->sin6_addr); } but the function always returns the IPv6 IP address since thats what the sa_family property is set as. My question is, is the IPv4 IP address stored anywhere in the data I'm using and, if so, how can I access it? Thanks so much in advance for all your help!

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  • Estimating the boundary of arbitrarily distributed data

    - by Dave
    I have two dimensional discrete spatial data. I would like to make an approximation of the spatial boundaries of this data so that I can produce a plot with another dataset on top of it. Ideally, this would be an ordered set of (x,y) points that matplotlib can plot with the plt.Polygon() patch. My initial attempt is very inelegant: I place a fine grid over the data, and where data is found in a cell, a square matplotlib patch is created of that cell. The resolution of the boundary thus depends on the sampling frequency of the grid. Here is an example, where the grey region are the cells containing data, black where no data exists. OK, problem solved - why am I still here? Well.... I'd like a more "elegant" solution, or at least one that is faster (ie. I don't want to get on with "real" work, I'd like to have some fun with this!). The best way I can think of is a ray-tracing approach - eg: from xmin to xmax, at y=ymin, check if data boundary crossed in intervals dx y=ymin+dy, do 1 do 1-2, but now sample in y An alternative is defining a centre, and sampling in r-theta space - ie radial spokes in dtheta increments. Both would produce a set of (x,y) points, but then how do I order/link neighbouring points them to create the boundary? A nearest neighbour approach is not appropriate as, for example (to borrow from Geography), an isthmus (think of Panama connecting N&S America) could then close off and isolate regions. This also might not deal very well with the holes seen in the data, which I would like to represent as a different plt.Polygon. The solution perhaps comes from solving an area maximisation problem. For a set of points defining the data limits, what is the maximum contiguous area contained within those points To form the enclosed area, what are the neighbouring points for the nth point? How will the holes be treated in this scheme - is this erring into topology now? Apologies, much of this is me thinking out loud. I'd be grateful for some hints, suggestions or solutions. I suspect this is an oft-studied problem with many solution techniques, but I'm looking for something simple to code and quick to run... I guess everyone is, really! Cheers, David

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  • Access violation when running native C++ application that uses a /clr built DLL

    - by doobop
    I'm reorganzing a legacy mixed (managed and unmanaged DLLs) application so that the main application segment is unmanaged MFC and that will call a C++ DLL compiled with /clr flag that will bridge the communication between the managed (C# DLLs) and unmanaged code. Unfortuantely, my changed have resulted in an Access violation that occurs before the application InitInstance() is called. This makes it very difficult to debug. The only information I get is the following stack trace. > 64006108() ntdll.dll!_ZwCreateMutant@16() + 0xc bytes kernel32.dll!_CreateMutexW@12() + 0x7a bytes So, here are some sceanrios I've tried. - Turned on Exceptions-Win32 Exceptions-c0000005 Access Violation to break when Thrown. Still the most detail I get is from the above stack trace. I've tried the application with F10, but it fails before any breakpoints are hit and fails with the above stack trace. - I've stubbed out the bridge DLL so that it only has one method that returns a bool and that method is coded to just return false (no C# code called). bool DllPassthrough::IsFailed() { return false; } If the stubbed out DLL is compiled with the /clr flag, the application fails. If it is compiled without the /clr flag, the application runs. - I've created a stub MFC application using the Visual Studio wizard for multidocument applications and call DllPassthrough::IsFailed(). This succeeds even with the /clr flag used to compile the DLL. - I've tried doing a manual LoadLibrary on winmm.lib as outlined in the following note Access violation when using c++/cli. The application still fails. So, my questions are how to solve the problem? Any hints, strategies, or previous incidents. And, failing that, how can I get more information on what code segment or library is causing the access exception? If I try more involved workarounds like doing LoadLibrary calls, I'd like to narrow it to the failing libraries. Thanks. BTW, we are using Visual Studio 2008 and the project is being built against the .NET 2.0 framework for the managed sections.

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  • Java Socket Connection is flooding network OR resulting in high ping

    - by user1461100
    i have a little problem with my java socket code. I'm writing an android client application which is sending data to a java multithreaded socket server on my pc through direct(!) wireless connection. It works fine but i want to improve it for mobile applications as it is very power consuming by now. When i remove two special lines in my code, the cpu usage of my mobile device (htc one x) is totally okay but then my connection seems to have high ping rates or something like that... Here is a server code snippet where i receive the clients data: while(true) { try { .... Object obj = in.readObject(); if(obj != null) { Class clazz = obj.getClass(); String className = clazz.getName(); if(className.equals("java.lang.String")) { String cmd = (String)obj; if(cmd.equals("dc")) { System.out.println("Client "+id+" disconnected!"); Server.connectedClients[id-1] = false; break; } if(cmd.substring(0,1).equals("!")) { robot.keyRelease(PlayerEnum.getKey(cmd,id)); } else { robot.keyPress(PlayerEnum.getKey(cmd,id)); } } } } catch .... Heres the client part, where i send my data in a while loop: private void networking() { try { if(client != null) { .... out.writeObject(sendQueue.poll()); .... } } catch .... when i write it this why, i send data everytime the while loop gets executed.. when sendQueue is empty, a null "Object" will be send. this results in "high" network traffic and in "high" cpu usage. BUT: all send comments are received nearly immediately. when i change the code to following: while(true) ... if(sendQueue.peek() != null) { out.writeObject(sendQueue.poll()); } ... the cpu usage is totally okay but i'm getting some laggs.. the commands do not arrive fast enough.. as i said, it works fine (besides cpu usage) if i'm sending data(with that null objects) every while execution. but i'm sure that this is very rough coding style because i'm kind of flooding the network. any hints? what am i doing wrong?? Thanks for your Help! Sincerly yours, maaft

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  • output with "Private`" Content in Mathematica Package

    - by madalina
    Hello everyone, I am trying to solve the following implementation problem in Mathematica 7.0 for some days now and I do not understand exactly what is happening so I hope someone can give me some hints. I have 3 functions that I implemented in Mathematica in a source file with extension *.nb. They are working okay to all the examples. Now I want to put these functions into 3 different packages. So I created three different packages with extension .*m in which I put all the desired Mathematica function. An example in the "stereographic.m" package which contain the code: BeginPackage["stereographic`"] stereographic::usage="The package stereographic...." formEqs::usage="The function formEqs[complexBivPolyEqn..." makePoly::usage="The function makePoly[algebraicEqn] ..." getFixPolys::usage="The function..." milnorFibration::usage="The function..." Begin["Private`"] Share[]; formEqs[complex_,{m_,n_}]:=Block[{complexnew,complexnew1, realeq, imageq, expreal, expimag, polyrealF, polyimagF,s,t,u,v,a,b,c,epsilon,x,y,z}, complexnew:=complex/.{m->s+I*t,n->u+I*v}; complexnew1:=complexnew/.{s->(2 a epsilon)/(1+a^2+b^2+c^2),t->(2 b epsilon)/(1+a^2+b^2+c^2),u->(2 c epsilon)/(1+a^2+b^2+c^2),v->(- epsilon+a^2 epsilon+b^2 epsilon+c^2 epsilon)/(1+a^2+b^2+c^2)}; realeq:=ComplexExpand[Re[complexnew1]]; imageq:=ComplexExpand[Im[complexnew1]]; expreal:=makePoly[realeq]; expimag:=makePoly[imageq]; polyrealF:=expreal/.{a->x,b->y,c->z}; polyimagF:=expimag/.{a->x,b->y,c->z}; {polyrealF,polyimagF} ] End[] EndPackage[] Now to test the function I load the package Needs["stereographic`"] everything is okay. But when I test the function for example with formEqs[x^2-y^2,{x,y}] I get the following ouput: {Private`epsilon^2 + 2 Private`x^2 Private`epsilon^2 + Private`x^4 Private`epsilon^2 - 6 Private`y^2 Private`epsilon^2 + 2 Private`x^2 Private`y^2 Private`epsilon^2 + Private`y^4 Private`epsilon^2 - 6 Private`z^2 Private`epsilon^2 + 2 Private`x^2 Private`z^2 Private`epsilon^2 + 2 Private`y^2 Private`z^2 Private`epsilon^2 + Private`z^4 Private`epsilon^2, 8 Private`x Private`y Private`epsilon^2 + 4 Private`z Private`epsilon^2 - 4 Private`x^2 Private`z Private`epsilon^2 - 4 Private`y^2 Private`z Private`epsilon^2 - 4 Private`z^3 Private`epsilon^2} Of course I do not understand why Private` appears in front of any local variable which I returned in the final result. I would want not to have this Private` in the computed output. Any idea or better explanations which could indicate me why this happens? Thank you very much for your help. Best wishes, madalina

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  • Rails learn's confusion

    - by Steve
    This is a beginner's rails learning confusion. When I learn rails, from time to time, I feel frustrated on rails' principle "Convention over Configuration". Rails uses heavily on conventions. A lot of them are just naming conventions. If I forget a convention, I will either use the wrong naming and get unexpected result or get things magically done but don't understand how. Sometimes, I think of configuration. At least configuration lists everything clearly and nothing is in fog. In rails, there seems a hidden, dark contract between you and the machine. If you follow the contract, you communicate well. But a beginner usually forgets items listed on the contract and this usually leads to confusion. That's why when I first pick up rails, I feel like it is somehow difficult to learn. Besides, there are many other things that could be new to a learner, such as using git, using plugins from community, using RESTful routing style, using RSpec. All these are new and come together in learning ruby and rails. This definitely adds up difficulties for a beginner. In contrast, if you learn php, it wouldn't be that bad. You can forget many things and focus on learning php itself. You don't need to learn database handling if you know SQL already(in rails, you need to learn a whole new concept migration), you don't have to learn a new decent unit test(in rails, usually they teach RSpec along the way because rails is agile and you should learn test-driven development in the early learning stage), you don't have to learn a new version control(in rails, you will be taught about git anyway), you don't have to use complicated plugins(in rails, they usually use third-party plugins in textbook examples! what the hell? why not teach how to do a simplified similar thing in rails?), you don't have to worry RESTful style. All in all, when I learn php, I learn it quick and soon I start to write things myself. Learning php is similar to learning C/java. It tastes like those traditional languages. When I learn rails, it is more difficult. And I need to learn ruby as well (I believe many of you learn ruby just because of rails). Does anyone have the similar feeling as I have? How do you overcome it and start to master rails? Hints will be welcomed. Thank you.

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  • Stored procedure performance randomly plummets; trivial ALTER fixes it. Why?

    - by gWiz
    I have a couple of stored procedures on SQL Server 2005 that I've noticed will suddenly take a significantly long time to complete when invoked from my ASP.NET MVC app running in an IIS6 web farm of four servers. Normal, expected completion time is less than a second; unexpected anomalous completion time is 25-45 seconds. The problem doesn't seem to ever correct itself. However, if I ALTER the stored procedure (even if I don't change anything in the procedure, except to perhaps add a space to the script created by SSMS Modify command), the completion time reverts to expected completion time. IIS and SQL Server are running on separate boxes, both running Windows Server 2003 R2 Enterprise Edition. SQL Server is Standard Edition. All machines have dual Xeon E5450 3GHz CPUs and 4GB RAM. SQL Server is accessed using its TCP/IP protocol over gigabit ethernet (not sure what physical medium). The problem is present from all web servers in the web farm. When I invoke the procedure from a query window in SSMS on my development machine, the procedure completes in normal time. This is strange because I was under the impression that SSMS used the same SqlClient driver as in .NET. When I point my development instance of the web app to the production database, I again get the anomalous long completion time. If my SqlCommand Timeout is too short, I get System.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Question: Why would performing ALTER on the stored procedure, without actually changing anything in it, restore the completion time to less than a second, as expected? Edit: To clarify, when the procedure is running slow for the app, it simultaneously runs fine in SSMS with the same parameters. The only difference I can discern is login credentials (next time I notice the behavior, I'll be checking from SSMS with the same creds). The ultimate goal is to get the procs to sustainably run with expected speed without requiring occasional intervention. Resolution: I wanted to to update this question in case others are experiencing this issue. Following the leads of the answers below, I was able to consistently reproduce this behavior. In order to test, I utilize sp_recompile and pass it one of the susceptible sprocs. I then initiate a website request from my browser that will invoke the sproc with atypical parameters. Lastly, I initiate a website request to a page that invokes the sproc with typical parameters, and observe that the request does not complete because of a SQL timeout on the sproc invocation. To resolve this on SQL Server 2005, I've added OPTIMIZE FOR hints to my SELECT. The sprocs that were vulnerable all have the "all-in-one" pattern described in this article. This pattern is certainly not ideal but was a necessary trade-off given the timeframe for the project.

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  • FB Connect going in an infinite loop with google chrome

    - by Mitesh
    Hi, I am having the following php code which i am trying for testing FB Connect <?php define('FACEBOOK_APP_ID', 'YOUR_APP_ID'); define('FACEBOOK_SECRET', 'YOUR_APP_SECRET'); function get_facebook_cookie($app_id, $application_secret) { enter code here $args = array(); parse_str(trim($COOKIE['fbs' . $app_id], '\"'), $args); ksort($args); $payload = ''; foreach ($args as $key = $value) { if ($key != 'sig') { $payload .= $key . '=' . $value; } } if (md5($payload . $application_secret) != $args['sig']) { return null; } return $args; } $cookie = get_facebook_cookie(FACEBOOK_APP_ID, FACEBOOK_SECRET); ? <!DOCTYPE html <html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2008/fbml" <body <?php if ($cookie) { ? Your user ID is <?= $cookie['uid'] ? <br / Your Acess Token is <br / <?php $user = json_decode(file_get_contents( 'https://graph.facebook.com/me?access_token=' . $cookie['access_token'])); if($user) { echo "<br /Display Name = " . $user-name; echo "<br /First Name = " . $user-first_name; echo "<br /Last Name = " . $user-last_name; echo "<br /Birthday = " . $user-birthday; echo "<br /Home Town = " . $user-hometown-name; echo "<br /Location = " . $user-location-name; echo "<br /Email = " . $user-email . "<br /"; } ? <?php } else { ? <fb:login-button perms="email,user_birthday,publish_stream"</fb:login-button <?php } ? <div id="fb-root">&lt;/div> <script src="http://connect.facebook.net/en_US/all.js"></script> <script> FB.init({appId: '<?= FACEBOOK_APP_ID ?>', status: true, cookie: true, xfbml: true}); FB.Event.subscribe('auth.login', function(response) { window.location.reload(); }); </script> </body </html The problem faced by me is it works fine with IE and Firefox, however when done the same with google chrome I am running into an infinite loop when I click on reload/refresh button of chrome after logging in. Any hints as to why is it happening with chrome? Also how can it be avoided. Thanks, Mitesh

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  • Convert string from getline into a number

    - by haskellguy
    I am trying to create a 2D array with vectors. I have a file that has for each line a set of numbers. So what I did I implemented a split function that every time I have a new number (separated by \t) it splits that and add it to the vector vector<double> &split(const string &s, char delim, vector<double> &elems) { stringstream ss(s); string item; while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; elems.push_back(number); } return elems; } vector<double> split(const string &s, char delim) { vector<double> elems; split(s, delim, elems); return elems; } After that I simply iterate through it. int main() { ifstream file("./data/file.txt"); string row; vector< vector<double> > matrix; int line_count = -1; while (getline(file, row)) { line_count++; if (line_count <= 4) continue; vector<double> cols = split(row, '\t'); matrix.push_back(cols); } ... } Now my issues is in this bit here: while (getline(ss, item, delim)) { cout << item << endl; double number = atof(item.c_str()); cout << number; Where item.c_str() is converted to a 0. Shouldn't that be still a string having the same value as item? It works on a separate example if I do straight from string to c_string, but when I use this getline I end up in this error situation, hints?

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